Small power generating device and water faucet device

ABSTRACT

A small generator includes a hydraulic turbine provided in a fluid path rotating with a passage of a fluid in a predetermined flow and a rotator coupled to the hydraulic turbine rotating together with the hydraulic turbine which acts as a rotor portion opposed to a stator portion having multiple layers in a stepping motor including the stator portion, wherein the rotor portion relatively rotates with respect to the stator portion with the passage of the fluid, thereby generating a power.

BACKGROUND OF INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to a small generator utilizing ahydroelectric generated by a water flow passing through a faucet and aWater tap apparatus contains a small generator is provided.

[0003] 2. Related Art

[0004] Conventionally, there is widely provided an automatic Water Tapapparatus contains a sensor sensing that a hand held out beneath afaucet. Then the faucet starts to flow water from is on the basis of thesensor sensing. In recent years, moreover, there is proposed anapparatus such that a small generator is provided in a fluid path ofsuch an automatic Water Tap apparatus and a power generated by the smallgenerator is storaged to complement for the power consumption of acircuit such as the sensor as shown in Japanese Utility ModelPublication Hei. 2-65775.

[0005] The structure of the small generator will be briefly describedbelow. A hydraulic turbine is provided in a fluid path to be a waterflowing path and rotates by receiving the hydroelectric of flowingwater. A rotor is fixed integrally with the rotary shaft of thehydraulic turbine. The outer peripheral surface of the rotor is amagnetized as a rotor magnet. The rotor magnet is opposed to a statorpole through the wall of a non-magnetic member. Moreover, single layerstator coil is provided to be interlinked with a magnetic flux passingthrough the stator pole. Then, the hydraulic turbine rotates byreceiving the hydroelectric of the flowing water so that a magnetrotates relatively with respect to the stator pole. Therefore, the flowof the magnetic flux flowing to the rotor and the stator pole ischanged. As a result, a current flows to the stator coil in such adirection as to prevent the change in the flow of the magnetic flux.After the current is rectified, it is stored in a storage battery.

[0006] As described above, the magnetic flux flows between the rotor andthe stator pole in the generator. The magnetic flux acts as a resistancewhen the hydraulic turbine is to be rotated by the hydroelectric causedby flowing the water. In other words, a magnetic flux generated betweenthe rotor and the stator pole acts as a detent torque to brake theoperation of the hydraulic turbine during the starting and rotation ofthe hydraulic turbine. Accordingly, in order to rotate the hydraulicturbine, it should receive a flow amount and a hydraulic pressure beyonda predetermined value. Therefore, if the flow amount is small or thehydraulic pressure of the flowing water received by the hydraulicturbine is low, the hydraulic turbine is neither rotated nor generates apower. If the magnetic force of the rotor magnet is low, the detenttorque is reduced so that the hydraulic turbine itself is rotatedConsequently, an induced voltage generated during the rotation of therotor is also dropped so that the amount of power generation isextremely increased. In order to obtain a desirable amount of powergeneration, it is necessary to increase the magnetic force of the rotormagnetic to some extent and to maintain the flow and hydraulic pressureof a fluid for rotating the hydraulic turbine to some extent.

[0007] Under such circumstances, in the small generator for theautomatic Water Tap apparatus which has been used widely, if the flow isspecifically set to 3 liters/minute or less, the detent torque acts as aresistance so that the hydraulic turbine cannot be smoothly rotated. Inorder to rotate the hydraulic turbine, it is necessary to set the flowmore than 3 liters/minute.

[0008] Water saving has been demanded for a long time in respect of theimprovement of the environment and other various problems. Under suchcircumstances, there has been a problem in that the amount of water toflow at a time should be reduced as much as possible also in theautomatic Water Tap apparatus. In addition, in the present situations inwhich a user's critical mind for water saving has been enhanced, thehydraulic pressure of the water discharged with the flow should also bereduced. It is necessary to give such an image that the water saving isbeing carried out through a drop in the hydraulic pressure.

SUMMARY OF INVENTION

[0009] It is an object of the invention to provide a small generatorcapable of rotating a water turbine with a small flow to generate asufficient amount of power and a Water Tap apparatus.

[0010] In consideration of the above-mentioned problems, according to anaspect to the present invention there is provided a small generatorcomprising a hydraulic turbine, provided in a fluid path, rotating bypassing a fluid in a predetermined flow rate, a rotator, coupled to thehydraulic turbine, rotating together with the hydraulic turbine, therotator acting as a rotor portion opposed to a stator portion havingmultiple layers in a stepping motor including the stator portion,wherein the rotor portion rotates relatively with respect to the statorportion by with passing the fluid to generate a power. Thus, the statorportion of the stepping motor for power generation is constituted bymultiple of layers. Therefore, each layer acts to cancel a detent torquebetween the stator portion and the rotor so that the detent torque canbe reduced. As a result, the hydraulic turbine can rotate with a smallflow at a low hydraulic pressure.

[0011] According to another aspect of the present invention, in additionto the aspect of the present invention described above, a detent torquegenerated between the stator portion and the rotor is set to becancelled by the layers each other. For example, the detent torque ispositively set to be reduced by skewing each layer (rotating the layerin a circumferential direction to intentionally shift a pole thereof) orproviding a non-magnetic member between the layers. Consequently, thefunctions can be obtained more effectively.

[0012] Moreover, according to another aspect of the present invention,there is provided a small generator comprising a hydraulic turbine,provided in a fluid path, rotating by passing a fluid in a predeterminedflow rate, a rotator, coupled to the hydraulic turbine, rotatingtogether with the hydraulic turbine, the rotator acting as a rotorportion opposed to a stator portion having a plurality of coil portionsin a brushless motor including the stator portion, wherein the rotorportion rotates relatively with respect to the stator portion by passingthe fluid to generate a power. Thus, the rotator coupled to thehydraulic turbine serves as the rotor portion opposed to the statorportion of the brushless motor. Therefore, it is possible to reduce thedetent torque than that in a conventional generator of a conventionalsingle layer type stepping motor. As a result, it is possible to rotatethe hydraulic turbine with a small flow at a low hydraulic pressure.

[0013] According to another aspect of the present invention, in additionto the aspect to the present invention described above, a relationshipbetween the number of poles magnetized onto the rotor portion and thenumber of coil portions of the stator portion is set to 2-3, 4-3 or 4-6.Consequently, it is possible to further reduce the detent torque betweenthe stator portion and the rotor portion.

[0014] According to another aspect of the present invention, in additionto the aspect of the present invention, there is provided an injectingmember including an injecting hole which acts as a part of the fluidpath and acts to throttle a flow for a passage to inject a fluid onto ablade portion of the hydraulic turbine. Consequently, it is possible toraise a hydraulic pressure to some extent through the injecting holeeven if the flow is small. Therefore, it is possible to rotate thehydraulic turbine more smoothly, thereby generating a power. Moreover,each of the small generators can generate a power with a small flow at alow pressure by reducing the detent torque. Therefore, it is alsopossible to generate a power without greatly raising the hydraulicpressure through an increase in the diameter of the injecting hole. Inthe case in which such setting is carried out, it is possible to reducea possibility that the injecting member might be damaged due to a highhydraulic pressure.

[0015] Furthermore, according to another aspect of the presentinvention, there is provided a Water Tap apparatus wherein a valveopening degree is controlled to include at least two modes of a watersaving mode in which a flow of a fluid to flow to a fluid path and anormal mode for a normal flow and the small generator of the presentinvention described in claims 6 to 9 is provided in the fluid path. Asdescribed above, the detent torque is reduced in the small generatoraccording to the present invention described in claims 6 to 9 which isprovided in the fluid path. Therefore, it is possible to generate apower with a small flow at a low hydraulic pressure. Therefore, if thehydraulic pressure of the fluid to be supplied to the hydraulic turbineis set to be low, it is possible to reduce a possibility that the membermight be damaged due to a high hydraulic pressure in the normal mode andto sufficiently generate a power also in the water saving mode.

[0016] According to a seventh aspect of the present invention, inaddition to the sixth aspect of the present invention, the flow in thewater saving mode is set to 2.0 liters/minute to 3.0 liters/minute.Therefore, the water saving can fully be carried out and the power canbe generated in a small amount of water.

BRIEF DESCRIPTION OF DRAWINGS

[0017]FIG. 1 is a longitudinal sectional view showing a small generatorof a two-layer stepping motor type according to a first embodiment ofthe invention;

[0018]FIG. 2 is a side view showing the small generator of FIG. 1 takenalong an arrow II in FIG. 1;

[0019]FIG. 3 is a bottom view showing the state of FIG. 2 taken along anarrow III,

[0020]FIG. 4 is a typical view showing the relationship between a member(nozzle ring) for spraying a fluid onto a hydraulic turbine in a statein which a hydraulic pressure is raised by throttling a fluid path andthe hydraulic turbine,

[0021]FIG. 5 is a longitudinal sectional view showing a small generatorof a brushless motor type according to a second embodiment of theinvention, and

[0022]FIG. 6 is a side view showing the small generator of FIG. 5 takenalong an arrow VI in FIG. 5.

[0023]FIG. 7(a) is a sectional side view of the water tap apparatuscontaining the small generator of the present invention;

[0024]FIG. 7(b) is a front sectional view.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0025] Each embodiment of a small generator and a Water Tap apparatusaccording to the invention will be described below in detail withreference to the drawings.

[0026] First Embodiment

[0027] Primary, a small generator utilizing a two-layer stepping motortype according to a first embodiment of the invention will be describedwith reference to FIGS. 1 to 4. FIG. 1 is a longitudinal sectional viewshowing a small generator of a two-layer stepping motor type accordingto the first embodiment of the invention. Moreover, FIG. 2 is a sideview showing the small generator of FIG. 1 taken along an arrow II inFIG. 1. Furthermore, FIG. 3 is a bottom view showing the state of FIG. 2taken along an arrow III. Moreover, FIG. 4 is a typical view showing arelationship between a member (nozzle ring) for spraying a fluid onto ahydraulic turbine in a state in which a hydraulic pressure is raised bythrottling a fluid path and the hydraulic turbine.

[0028] As shown in FIG. 1, the small generator utilizing a two-layerstepping motor type according to the first embodiment comprises a casing1, a nozzle ring 2 provided in the casing 1, a hydraulic turbine 3rotatably provided on the inner peripheral side of the nozzle ring 2, arotor 4 rotating integrally with the hydraulic turbine 3, a cup-shapedmember 5 formed of stainless which is provided on the outer peripheralside of the rotor 4, and a stator portion 6 of a stepping motor which isfurther provided on the outside of the cup-shaped member 5.

[0029] As shown in FIGS. 1 and 2, the casing 1 includes a body portion11, and an inlet path 12 and an outlet path 13 which are protrudedtoward the outside of the body portion 11. The body portion 11 has ageneration part attaching portion 11 a for attaching a generation partconstituted by the rotor 4 and the stator portion 6. The generation partattaching portion 11 a is constituted by an open end face portion formedon the right side of the body portion 11 in FIG. 1 and an outerperipheral portion thereof, and a circumferential groove 11 b is formedin the outer peripheral portion. An O ring 8 is embedded in the groove11 b.

[0030] Furthermore, a flange portion 52 of the cup-shaped member 5 ispushed to seal the O ring 8 in the groove 11 b and a cover member 9 isprovided to interpose the flange portion 52 of the cup-shaped member 5together with the generation part attaching portion 11 a in a state inwhich the outer peripheral end of the flange portion 52 is caused toabut on a convex portion 11 d formed in the body portion 11 (see theenlarged view of FIG. 1). More specifically, the cup-shaped member 5 ispushed against the generation part attaching portion 11 a while crushingthe O ring 8 in the groove 11 b, and furthermore, the cover member 9covers from above. When the outer peripheral end of the flange portion52 of the cup-shaped member 5 is thus caused to abut on the innerperipheral part of the convex portion 11 d, the cup-shaped member 5 ispositioned in the inner peripheral part of the stator portion 6. Asshown in FIG. 2, four screws 10 are inserted in screw holes formed onfour corners of the cover member 9 for screwing so that the coverportion 9 is fixed to the body portion 11 of the casing 1. Consequently,the generation part attaching portion 11 a to be the open end face ofthe casing 1 is closed by the cup-shaped member 5.

[0031] The cup-shaped member 5 is formed of a non-magnetic stainlessmember, and has the flange portion 52, a cylindrical portion 51 and abottom portion 53 formed through throttling. A bearing 15 for rotatablyreceiving one of ends of a shaft 7 supporting the hydraulic turbine 3and the rotor 4 is fitted in the bottom portion 53. The cup-shapedmember 5 serves to separate the stator portion 6 of the stepping motorfrom a fluid passing through the inside of the casing 1 and to preventthe fluid from flowing out of the casing 1.

[0032] The inlet path 12 and the outlet path 13 which are formed in thecasing 1 and a coupling path 14 for coupling them are provided in a partof a fluid path of a Water Tap apparatus (as shown in FIG. 7)constituted by a faucet, a valve and the like, and a fluid entering theinlet path 12 from a fluid source passes through the coupling path 14and is then discharged from the outlet path 13. The fluid serves to givethe rotating force to the hydraulic turbine 3 during the passage. Thisportion will be described below in detail. The other end of the shaft 7supporting the rotation of the hydraulic turbine 3 and the rotor 4 whichwill be described below is rotatably provided in the coupling path 14.One of ends of the shaft 7 is rotatably fitted in a hole 14 a for abearing which is formed in the coupling path 14 of the casing 1 and theother end side thereof is rotatably fitted in the bearing 15 having atip provided in the cup-shaped member 5 through the open end face.Consequently, the shaft 7 is held by cooperate the casing 1 with thecup-shaped member 5.

[0033] The nozzle ring 2 to be an injecting member acting as a part ofthe fluid path of the Water Tap apparatus and serving to throttle theflow of the passing fluid and to inject the fluid to a blade portion 31(see FIG. 4) of the hydraulic turbine 3 is fitted in the coupling path14 of the casing 1 by pressure. The nozzle ring 2 has an cylindricalring portion 21 and a flange portion 22 formed by bending one of openends of the ring portion 21 in a peripheral direction. Two nozzles 23are provided in symmetrical positions by approximately 180 degrees inthe ring portion 21 as shown in FIG. 4 in such a manner that the twonozzles 23 serve as injecting holes for throttling an inlet passage ofthe fluid entering the inlet path 12 and for injecting the fluid to theblade portion 31 of the hydraulic turbine 3 disposed on the inside.

[0034] The hydraulic turbine 3, provided in the nozzle ring 2 to be apart of the fluid path, rotates with the passage of the fluid in apredetermined flow. The hydraulic turbine 3 includes a cylindrical ringportion 32 and the blade portion 31 having an outer peripheral tipportion connected to one of side end faces of the ring portion 32 and acentral portion inserted and fixed to the shaft 7. The blade portion 31is curved circularly to easily receive the pressure of the fluid fromthe nozzle 23. For this reason, the fluid which enters the inlet path 12and is then throttled with the two nozzles 23 to have a pressure raisedhits on the blade portion 31 of the hydraulic turbine 3 vigorously andthe hydraulic turbine 3 rotates around the shaft 7 by the hydroelectricthereof. The fluid hitting on the blade portion 31 is moved from thecoupling path 14 to the outlet path 13 through the open part of thehydraulic turbine 3 and the inner peripheral part of the ring portion32.

[0035] The rotor 4 is formed integrally through the hydraulic turbine 3and a coupling shaft portion 35 and is provided coaxially with thehydraulic turbine 3. More specifically, the hydraulic turbine 3, thecoupling shaft portion 35 and the rotor 4 are coupled in a direction ofextension of the shaft 7. Therefore, when the hydraulic turbine 3rotates by the hydroelectric, the rotor 4 rotates around the shaft 7integrally with the hydraulic turbine 3. Four communicating holes 4 acommunicating in the direction of extension of the shaft 7 are formed onthe coupling portion 35 and the rotor 4 at regular intervals in acircumferential direction. These communicating holes 4 a serve to givesmooth rotation of the shaft 7 with respect to the bearing 15 by causingthe fluid to flow into the right side of the rotor 4 in FIG. 1.

[0036] The rotor 4 serves as the rotor portion of the stepping motor insuch a manner that the rotor 4 is coupled to the hydraulic turbine 3rotating together with the hydraulic turbine 3, and is constituted by arotor magnet Mg having eight poles magnetized onto an outer peripheralsurface thereof. The outer peripheral surface is opposed to the statorportion 6 of the stepping motor through the cylindrical portion 51 ofthe cup-shaped member 5. For this reason, in the case in which the rotor4 rotates together with the hydraulic turbine 3, it rotates relativelywith respect to the stator portion 6.

[0037] The stator portion 6 is constituted by two layers 6 a and 6 bwhich are superposed in an axial direction. Each of the layers 6 a and 6b includes an outer yoke (provided on the outside in a state ofsuperposition) 61, an outer pole tooth 61 a formed integrally with theouter yoke 61, an inner yoke (provided on the inside in the state ofsuperposition) 62, an inner pole tooth 62 a formed integrally with theinner yoke 62, and a coil 63 wound onto a coil bobbin. Start and endportions for winding the coil 63 are connected to a terminal 64,respectively.

[0038] The stator portion 6 thus constituted is fitted in the outsidepart of the cylindrical portion 51 of the cup-shaped member 5.Therefore, a magnetic flux flows between the pole teeth 61 a and 62 a ofthe stator portion 6 and the magnetized portion of the rotor 4. Asdescribed, when the rotor 4 rotates together with the hydraulic turbine3, the flow of the magnetic flux is changed so that an induced voltageis generated on the coil 63 in such a direction as to prevent the changein the flow. The induced voltage is taken out of the terminal 64. Theinduced voltage lead in such a form is converted into a direct currentthrough a circuit, and the direct current is then rectified through apredetermined circuit (not shown) and is charged into a battery.

[0039] A specific flow for rotating the hydraulic turbine 3 will bedescribed below. The rotating force received by the hydraulic turbine 3is set by the flow and hydraulic pressure of the fluid. In other words,the fluid entering the inlet 12 is throttled by the nozzle 23 to someextent and is caused to vigorously hit on the blade portion 31 of thehydraulic turbine 3. Consequently, the hydraulic turbine 3 receives therotating force from the fluid. As a matter of course, even if thehydraulic pressure is not raised by throttling the fluid path throughthe nozzle 23, the hydraulic turbine 3 can rotate with a sufficient flowitself. However, if the fluid is caused to hit on the blade portion 31of the hydraulic turbine 3 in a state in which the hydraulic pressure israised by the nozzle 23, it is possible to rotate the hydraulic turbine3 with a smaller flow.

[0040] In the embodiment, the fluid path is throttled to raise thehydraulic pressure. However, if the hydraulic pressure is too raised,there is also a possibility that the blade portion 31 of the hydraulicturbine 3, the nozzle ring 2 and other fluid paths for a fluid might bebroken. To the contrary, if the hydraulic pressure is too low, the flowbecomes insufficient so that power generation cannot fully be carriedout. For this reason, it is necessary to properly set the hydraulicpressure in respect of the materials and thicknesses of the hydraulicturbine 3 and the nozzle ring 2.

[0041] In addition to the shape of the blade portion 31 of the hydraulicturbine 3 and the total weight of the hydraulic turbine 3 (including theweight of the rotor 4), a detent torque generated between the rotor 4and the stator portion 6 acts as a resistance to be opposite to therotating force. The invention has a main object to reduce a detenttorque portion. In the embodiment, the stator portion 6 has a two-layerstructure and is skewed (each layer is shifted in a circumferentialdirection). Consequently, the pole tooth positions are shifted in thecircumferential direction, for example, and the detent torques generatedbetween the pole teeth and the magnetized portion of the rotor 4 to bethe rotor portion are cancelled from each other. Consequently, thedetent torque is reduced. Therefore, the detent torque between the rotor4 and the stator portion 6 which is generated during the rotation of thehydraulic turbine 3 does not effect as a very strong brake and thehydraulic turbine 3 can rotate smoothly with a small flow at a lowhydraulic pressure together with the rotor 4.

[0042] In the embodiment, thus, the stator portion 6 of the steppingmotor has the two-layer structure and the shape and thickness of theblade portion 31 are set to predetermined dimensions. Consequently, thehydraulic turbine 3 can rotate by utilizing a fluid flowing into theinlet path 12 with 2.0 to 3.0 liters/minute.

[0043] In the embodiment, moreover, a minimum starting current amount atwhich a generator starts to be rotated is set to approximately 1.2 to1.5 liters/minute. However, the amount of power generation is small.Furthermore, a voltage required for storage in a capacitor which is notshown is at least 5V or more in consideration of a conversion from AC toDC. Although a power can be generated with a slightly smaller flow than2.0 liters/minute in the embodiment, a flow of 2.0 liters/minute of moreis required for actually generating a power reliably.

[0044] On the other hand, the flow rate of 2.0 liters/minute is actuallyused as a minimum flow rate for washing hands. From the foregoing, inthe embodiment, a flow rate of 2.0 to 3.0 liters/minute is set to be awater saving mode and a flow rate which is greater than 3.0liters/minute is set to be a normal mode.

[0045] If the stator portion 6 has a single layer structure and otherportions are the same as those of the embodiment, the detent torque actsas the brake more strongly than that in the embodiment described above.More specifically, the hydraulic turbine 3 can rotate with a flow ratewhich is greater than 3 liters/minute.

[0046] Second Embodiment

[0047] Next, a small generator utilizing a brushless motor typeaccording to a second embodiment of the invention will be described withreference to FIGS. 5 and 6. In the description of the second embodiment,the description of the same structures as those in the first embodimentwill be omitted and the same components have the same reference numeralsas those in the first embodiment. FIG. 5 is a longitudinal sectionalview showing a small generator according to the second embodiment of theinvention. Moreover, FIG. 6 is a side view showing the small generatorof FIG. 5 taken along an arrow VI in FIG. 5.

[0048] As shown in FIG. 5, the small generator utilizing a brushlessmotor type according to the second embodiment has almost the samestructure as that in the first embodiment, and includes a casing 1, anozzle ring 2 provided in the casing 1, a hydraulic turbine 3 rotatablyprovided on the inner peripheral side of the nozzle ring 2, a rotor 4rotates integrally with the hydraulic turbine 3, a cup-shaped member 105formed of stainless which is provided on the outer peripheral side ofthe rotor 4, and a stator portion 106 of a brushless motor which isfurther provided on the outside of the cup-shaped member 105.

[0049] A body portion 111 of the casing 1 has a generation partattaching portion 111 a for attaching a generation part constituted bythe rotor 4 and the stator portion 106. The generation part attachingportion 111 a is constituted by a concave portion 111 c having a hole ina central part formed on the right side of the body portion 111 in FIG.1 and an outer peripheral portion thereof, and a circumferential groove111 b is formed in the outer peripheral portion. An O ring 8 is embeddedin the groove 111 b.

[0050] Furthermore, a flange portion 152 formed in the outermostperipheral portion of the cup-shaped member 105 is pushed to seal the Oring 8 in the groove 111 b and a cup-shaped member 90 is provided tointerpose the outer peripheral end of the flange portion 152 togetherwith the generation part attaching portion 111 a in a state in which theouter peripheral end of the flange portion 152 is caused to abut on aconvex portion (which is not shown and has the same structure as that ofthe first embodiment) formed in the body portion 111. More specifically,the cup-shaped member 105 is pushed against the generation partattaching portion 111 a while crushing the O ring 8 in the groove 111 b,and furthermore, the cup-shaped member 90 is provided from above. Asshown in FIG. 6, four screws 10 are inserted in screw holes formed onfour corners of the cup-shaped member 90 for screwing so that thecup-shaped member 90 is fixed to the body portion 111 of the casing 1.Consequently, the generation part attaching portion 111 a to be the openend face of the casing 1 is closed by the cup-shaped member 105.

[0051] The cup-shaped member 105 is formed of a non-magnetic stainlessmember, and is provided with the flange portion 152 through throttling,an outer cylindrical portion 155 connected to the flange portion 152, aninner cylindrical portion 151 provided on the inside of the outercylindrical portion, a coupled surface potion 156 coupling bothcylindrical portions 151 and 155, and a bottom portion 153. Thecup-shaped member 105 thus constituted is fitted in the concave portion111 c of the generation part attaching portion 111 a and is interposedand fixed between the casing 1 and the cup-shaped member 90 as describedabove. A bearing 15 for rotatably receiving one of ends of a shaft 7supporting the hydraulic turbine 3 and the rotor 4 is fitted in thebottom portion 153. The cup-shaped member 105 serves to separate thestator portion 106 of the brushless motor from a fluid passing throughthe inside of the casing 1 and to prevent the fluid from flowing out ofthe casing 1.

[0052] The nozzle ring 2 is press-fitted in the coupling path 14 of thecasing 1 in such a manner that the nozzle ring 2 acts to an injectingmember serving as a part of the fluid path of the Water Tap apparatusand effecting to throttle the flow of the passing fluid and to injectthe fluid to a blade portion 31 of the hydraulic turbine 3. Thestructure of the nozzle ring 2 is the same as that of the firstembodiment. Moreover, the structures of the hydraulic turbine 3 providedon the inside of the nozzle ring 2 and the rotor 4 formed integrallywith the hydraulic turbine 3 are also the same as those of the firstembodiment.

[0053] The rotor 4 serves as the rotor portion of the brushless motor insuch a manner that the rotor 4 coupled to the hydraulic turbine 3rotates together with the hydraulic turbine 3, and is constituted by arotor magnet Mg having two poles magnetized onto an outer peripheralsurface thereof. The outer peripheral surface is opposed to the statorportion 106 of the brushless motor through the inner cylindrical portion151 of the cup-shaped member 105. For this reason, in the case where therotor 4 rotates together with the hydraulic turbine 3, it rotatesrelatively with respect to the stator portion 106.

[0054] The stator portion 6 is constituted by three coil portions 106 a,106 b and 106 c provided at regular intervals in a circumferentialdirection as shown in FIG. 6. Each of the coil portions 106 a, 106 b and106 c includes a stator core 161 and a coil 163 wound onto the statorcore 161. Start and end portions for winding the coil 163 are connectedto a terminal 164, respectively.

[0055] The stator portion 106 thus constituted is fitted in a portionbetween the inner cylindrical portion 151 of the cup-shaped member 105and the outer cylindrical portion 155. For this reason, a magnetic fluxflows between an inner opposed surface 161 a of each yoke member 161 tobe a pole of the stator portion 106 and the magnetized portion of therotor 4. As described above, when the rotor 4 rotates together with thehydraulic turbine 3, the flow of the magnetic flux is changed so that aninduced voltage is generated on the coil 163 in such a direction as toprevent the change in the flow. The induced voltage is taken out of theterminal 164.

[0056] The induced voltage taken out in such a form is converted into adirect current through a circuit. An AC voltage induced by thegeneration part having an output coil to be a three-phase Y connectionis rectified through a three-phase bridge circuit (not shown) having sixdiodes and one smoothing capacitor and is converted into a directcurrent to be charged into a battery.

[0057] The stator portion 106 is constituted by the three coil portions106 a, 106 b and 106 c as described above and has three poles. On theother hand, the rotor 4 opposed to the stator portion 6 is two-polemagnetized as described above. More specifically, in the embodiment, thebrushless motor type is used and the number of poles magnetized onto therotor (rotor portion) 4 and the number of coil portions (the number ofpoles) of the stator portion 106 have a relationship of 2-3. For thisreason, a detent torque generated between the stator portion 106 and thestator 4 is not so great as that in the conventional single layerstepping motor type. Consequently, the detent torque between the rotor 4and the stator portion 106 which is generated during the rotation of thehydraulic turbine 3 does not act as a very great brake and the hydraulicturbine 3 can rotate smoothly with a small flow at a low hydraulicpressure together with the rotor 4.

[0058] The relationship between the number of poles magnetized onto therotor (rotor portion) 4 and the number of coil portions (the number ofpoles) of the stator portion 106 may be 4-3 or 4-6 in place of 2-3 inthe embodiment, for example. Also in the second embodiment in which themain part of the generator is thus constituted by the brushless motortype, the hydraulic turbine 3 can rotate by utilizing a fluid flowinginto an inlet path 12 with 2.0 to 3.0 liters/minute in the same manneras in the first embodiment.

[0059] If the structure of the generator has a stepping motor type andthe stator portion has a single layer structure (the stator portion hasthe two-layer structure in the first embodiment), the detent torque isgreat and acts as a brake as described above. More specifically, thehydraulic turbine 3 can rotate with a flow of 3 liters/minute or more.As described above, it is possible to generate a power in a small amountof water by causing the structure of the main part of the generator tohave the brushless motor type.

[0060] The small generator according to each of the embodiments cangenerate a power by utilizing a small flow of 2.0 to 3.0 liters/minute.In addition, also in the case in which the flow is more than 3.0liters/minute, it is a matter of course that the power can be generated.In addition, the rotor 4 rotates smoothly without an influence of thedetent torque. Therefore, a generation output per rotation speed ishigher than that in the conventional art.

[0061] There are such effects. In a Water Tap apparatus having the smallgenerator according to each of the embodiments attached thereto,therefore, a valve opening degree is controlled to include at least twomode specifications such as a water saving mode in which a flow of thefluid to flow to the fluid path is set to be smaller than usual and anormal mode in which the flow is normal, and the flow in the watersaving mode may be set to 2.0 to 3.0 liters/minute as described above.Thus, the power can be generated in the water saving mode and thegeneration output having a high efficiency can be obtained in the normalmode.

[0062] In each of the embodiments, as described above, it is possible tomore reduce the detent torque than that in the conventional steppingmotor type having a single layer structure. Therefore, a hole diameterof the nozzle 23 may be increased to reduce a hydraulic pressure to beapplied to the hydraulic turbine 3, for example, and it is also possibleto further reduce a possibility that the nozzle ring 2 and the hydraulicturbine 3 might be broken due to the hydraulic pressure. In that case,the lowest flow with which the hydraulic turbine 3 can rotate isslightly raised corresponding to the increase in the hole diameter ofthe nozzle 23 and the reduction in the hydraulic pressure. If the flowis approximately 2.5 liters/minute, for example, much higher performancecan be obtained as compared with that in the conventional art.

[0063] Next, a water tap apparatus employing the small generator of thepresent invention described above will be described below more indetail.

[0064] FIGS. 7(a) and (b) show sectional views of the water tapapparatus containing the small generator of the present invention. FIG.8 is a block diagram of relationship among a small generator, acapacitor and a controller.

[0065] In FIGS. 7(a) and (b), a water tap 1000 contains a spout and ahuman body detecting sensor 1001 for detecting a hand. The followingparts are provided in the water tap 1000, that is, a solenoid valve 1002opens and closes water flow, a small generator 1005 is shown in FIG. 1or 5, a controller 1003 for controlling the opening/closing of thesolenoid valve 1002 includes a DC converter (not shown) for convertingan induced voltage to a direct current and a rectifier circuit forrectifying the direct current, and a capacitor 1004 storages a rectifiedcurrent.

[0066] Next, the water tap 1000 operation will be described hereinbelow.When a human hand is detected by the sensor 1001, a signal send from thesensor 1001 to the controller 1003. The controller 1003 outputs the opensignal to the solenoid valve 1002. Then, the solenoid valve open tospout a water. The water flows in the tube located in the water tap toreach the small generator 1005. In the small generator 1005, the waterentering into the inlet path is throttled by the nozzle or the like toincrease the hydraulic pressure. Then water hits on the blade portion ofthe hydraulic turbine to generate an induced voltage. The inducedvoltage is converted to the direct current by the DC converter (notshown) and rectified by passing through the rectifier circuit (notshown) to storage the capacitor (not shown).

[0067] Then, the current storaged in the capacitor (not shown) isapplied to the controller 1002.

[0068] On the other hand, when the human hand is not detected, thesensor 1001 recognizes the condition to output a signal to thecontroller 1002 to close the solenoid valve 1003.

[0069] The water tap 1000 operation is not limited by this embodimentdescribed above. The following operation could be employed such thatafter spouting a predetermined amount of the water, the water flow isautomatically stopped.

[0070] In the small generator according to the invention, the rotorcoupled to the hydraulic turbine which rotates through the passage ofthe fluid acts as the rotor portion opposed to the stator portion havingmultiple layers in the stepping motor including the stator portion.Therefore, each layer acts to cancel a detent torque between the statorportion and the rotor so that the detent torque can be reduced. As aresult, the hydraulic turbine can rotate with a low flow at a lowhydraulic pressure.

[0071] In the small generator according to another invention, moreover,the rotor coupled to the hydraulic turbine which rotates through thepassage of the fluid serves as the rotor portion opposed to the statorportion of the brushless motor including the stator portion having aplurality of coil portions. Consequently, it is possible to reduce thedetent torque. As a result, it is possible to rotate the hydraulicturbine with a small flow at a low hydraulic pressure.

[0072] Furthermore, the Water Tap apparatus according to the inventionhas at least two modes of a water saving mode and a normal mode bycontrolling the valve opening degree, and is provided with the smallgenerator in the fluid path. In the Water Tap apparatus according to theinvention, thus, the small generator having a detent torque reduced isprovided in the fluid path so that the power can be generated with asmall flow at a low hydraulic pressure. Consequently, if the hydraulicpressure of the fluid to be supplied to the hydraulic turbine is set tobe low, it is possible to reduce a possibility that a member might bedamaged at a high hydraulic pressure in the normal mode and a power canfully be generated also in the water saving mode.

What is claimed is:
 1. A small generator comprising: a hydraulicturbine, provided in a fluid path, rotating by passing a fluid in apredetermined flow rate; a rotator, coupled to the hydraulic turbine,rotating together with the hydraulic turbine, the rotator acting as arotor portion opposed to a stator portion having multiple layers in astepping motor including the stator portion, wherein the rotor portionrotates relatively with respect to the stator portion by with passingthe fluid to generate a power.
 2. The small generator according to claim1, wherein a detent torque generated between the stator portion and therotor is set to be canceled-by arranging the layers each other.
 3. Asmall generator comprising: a hydraulic turbine, provided in a fluidpath, rotating by passing a fluid in a predetermined flow rate; arotator, coupled to the hydraulic turbine, rotating together with thehydraulic turbine, the rotator acting as a rotor portion opposed to astator portion having a plurality of coil portions in a brushless motorincluding the stator portion, wherein the rotor portion relativelyrotates with respect to the stator portion by passing the fluid togenerate a power.
 4. The small generator according to claim 3, wherein arelationship between the number of poles magnetized onto the rotorportion and the number of coil portions of the stator portion is set toone of 2-3, 4-3 and 4-6.
 5. The small generator according to claim 1,further comprising: an injecting member including an injecting holeacting as a part of the fluid path and serving to throttle a flow for apassage to inject a fluid onto a blade portion of the hydraulic turbine.6. A Water Tap apparatus comprising: a valve opening degree controlledto include at least two modes of a water saving mode in which a flow ofa fluid to flow to a fluid path and a normal mode for a normal and asmall generator according to claim 1 arranged on the fluid.
 7. The WaterTap apparatus according to claim 6, wherein the flow in the water savingmode is set to 2.0 liters/minute to 3.0 liters/minute.
 8. The smallgenerator according to claim 3, further comprising: an injecting memberincluding an injecting hole acting as a part of the fluid path andserving to throttle a flow for a passage to inject a fluid onto a bladeportion of the hydraulic turbine.
 9. A Water Tap apparatus comprising: avalve opening degree is controlled to include at least two modes of awater saving mode in which a flow of a fluid to flow to a fluid path anda normal mode for a normal flow; and a small generator according toclaim 3 arranged on the fluid.
 10. The Water Tap apparatus according toclaim 9, wherein the flow in the water saving mode is set to 2.0 to 3.0liter/minute.